1. Field of the Invention
The present invention relates to an image forming apparatus represented by, for example, an electrostatic copying machine and a laser beam printer, and, more particularly to a color image forming apparatus capable of providing a color image on the basis of a subtractive process.
2. Description of the Related Art
A color image forming apparatus capable of providing a color image on the basis of a subtractive process has already been put to practical use and widely used.
In Japanese Patent Disclosure (KOKAI) No. 2005-221870 or Japanese Patent Disclosure (KOKAI) No. 2001-296715, an image forming apparatus in which developing units that provide images of respective colors of yellow (Y), magenta (M), and Cyan (C) and a developing unit that provides an image of Black (BK) are arranged in one row along a transfer belt is described.
However, in the image forming apparatus described in the two publications, when, in order to increase a toner volume of a developing unit for a specific color, for example, BK, an interval between the BK developing unit and a developing unit of a color adjacent to the BK developing unit is set wider than intervals among the developing units of the other colors, a distance from an exposing unit to an imaging plane (a photosensitive drum on which an image to be transferred onto the transfer belt is formed) changes, making it difficult to design the exposing unit.